Atlas track, working with 20x10 space

It may be better to follow a process like Givens and Druthers. When you have that completed, what your layout needs to be will reveal itself. For example, if operations of a specific railroad is part of your Druthers, you can view maps (past and current) or satellite views and select those elements to include. A fully operational yard can take up to 5'-6' x 20'.

If you would like a more of a display type of layout for primarily running multiple trains simultaneously, then the design and elements will be different. Then having something like a run-through yard for staging complete trains will need to be an element.

 

Using scale circles on a scale 10 x 20 rectangle will reveal how curves and loops will fit.

 

Here's a quick read that touches on the process of a few of the well known layout designers. This may help start you on your way.

 

Don't discount oval loops and what you can create from that shape.

It sounds like you're leaning towards a walk-around layout- that does give you alot of real estate to work with, but anything past your reach will need to be accessed with pop-up hatches and alot of crawling. It also means alot of scenery needs to be done to make it look even somewhat realistic. An island-style layout does give you alot of room for sweeping curves, but you'll want to have something in the middle (town, industry, hills, etc.) to keep the trains from looking like they're just going around in circles- tunnels and some hidden track sections help there. Most people with your space go with a multi-level 'dogbone' track plan and put the town and yard in the middle. Changes in grade can be done either on open or hidden track, but it's possible to do both as well.

 

I have a 20 x 20 family room and my first attempt at a layout was an L-shaped design with 40.5" and 36" radius turns at the ends. I had plenty of room for both a town and a yard, and had plans to run additional yard trackage under the layout, as well as have an elevated high line that would run about 12" higher than the main level, but sadly I lost my right-of-way rights and the benchwork was ordered to be removed. I eventually chopped up alot of the benchwork, but kept my 2 x 6 modules for a more modest, portable around-the-walls layout that can be assembled, removed and stored.

 

Geno

 

 

This was done with O 54 outer loop and O 45 inner loop.  12'6" X 12'

Addition/Remodel adds  another 12' X 7' tapered to 3'.

Last addition  12' X 7' across a doorway.

Camera walk around. Click on the link to access.
http://s175.photobucket.com/us...mera%20walk%20around
Track drawings were to with an Atlas freeware that is no longer available.